Rapidly heating and cooling composite mats comprised of cellulose and thermoplastic polymer

ABSTRACT

In accordance with some aspects of the present disclosure, a method producing a composite board comprising plastic and cellulose is described. The method includes transmitting a first signal to a pair of opposing hot-platens, receipt of the first signal causing the pair of opposing hot-platens to compress and heat a composite mat; transmitting a second signal to the pair of opposing hot-platens, receipt of the second signal causing the pair of opposing hot-platens to heat and compress the composite mat at substantially a first pressure for a first time period; transmitting a third signal to the pair of opposing hot-platens, receipt of the third signal causing the pair of opposing hot-platens to release the composite mat from the first pressure; and transmitting a fourth signal to a pair of opposing cold-platens, receipt of the fourth signal causing the pair of opposing cold-platens to compress and cool the composite mat.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.17/171,766, filed on Feb. 9, 2021, the entire disclosure of which isincorporated by reference herein.

BACKGROUND

Effective and environmentally sound waste disposal is a common dilemmafaced by most industrialized and developing nations. In recent history,waste has primarily been disposed of in landfills, which requiresubstantial tracts of land that might otherwise be used for othermeaningful purposes. Regulatory and political bodies, as well asgenerators of waste, are increasingly interested in reducing wastevolumes, diverting waste from landfills and incinerators while promotingmore sustainable usage of waste products. Unfortunately, despite effortsof governments and communities to institute and promote waste recyclingprograms, there remains a tremendous amount of recyclable material thatis not recycled.

There is a critical need to utilize this vast resource and at the sametime save the land now occupied as landfill space. It is thereforedesirable to develop technologies that not only reduce the amount ofwaste destined for a landfill or incinerator, but also to capture anduse such material for beneficial purposes.

SUMMARY

In accordance with some aspects of the present disclosure, a system forproducing a composite board comprised of plastic and cellulose isdisclosed. The system may include a mat formation assembly stageconfigured to form a composite mat comprising plastic, cellulosecomponents, and water, the composite mat having a core at a midpointbetween a proximate end and a distal end of the composite mat; one ormore pairs of opposing hot-platens that are used in a hot-pressingstage; one or more pairs of opposing cold-platens that are used in acold-pressing stage that occurs after the hot-pressing stage; and aprocessor coupled to a memory having programmed instructions, whereinupon executing the programmed instructions, the processor: transmits afirst signal to the one or more pairs of opposing hot-platens, receiptof the first signal causing the one or more pairs of opposinghot-platens to compress and heat the composite mat; receives, from apressure sensor coupled to the one or more pairs of opposinghot-platens, indications of pressure the one or more pairs of opposinghot-platens exerts while compressing the composite mat; based on theindications, transmits a second signal to the one or more pairs ofopposing hot-platens, receipt of the second signal causing the one ormore pairs of opposing hot-platens to heat and compress the compositemat at substantially a first pressure to superheat the water such that atemperature of the water remains above a boiling temperature of thewater at a standard atmospheric pressure without the water changing froma liquid state to a gaseous state for a first time period sufficient forthe core of the composite mat to reach a first target temperature;transmits a third signal to the one or more pairs of opposinghot-platens, receipt of the third signal causing the one or more pairsof opposing hot-platens to release the composite mat from the firstpressure after the first time period, wherein releasing the compositemat causes the superheated water in the mat to change from a liquidstate to a gaseous state; and transmits a fourth signal to the one ormore pairs of opposing cold-platens, receipt of the fourth signalcausing the one or more pairs of opposing cold-platens to compress andcool the composite mat for a second time period sufficient for the coreof the composite mat to reach a second target temperature.

In accordance with some aspects of the present disclosure, a method forproducing a composite board comprised of plastic and cellulose isdisclosed. transmitting, by a processor, a first signal to one or morepairs of opposing hot-platens of a manufacturing apparatus, the one ormore pairs of opposing hot-platens heating and compressing a compositemat comprising plastic, cellulose, and water, the composite mat having acore at a midpoint between a first end and a distal end of the compositemat, receipt of the first signal causing the one or more pairs ofopposing hot-platens to compress and heat the composite mat; receiving,by the processor from a pressure sensor coupled to the one or more pairsof opposing hot-platens, indications of pressure the one or more pair ofopposing hot-platens exerts while compressing the composite mat; basedon the indications, transmitting, by the processor, a second signal tothe one or more pairs of opposing hot-platens, receipt of the secondsignal causing the one or more pairs of opposing hot-platens to heat andcompress the composite mat at substantially a first pressure tosuperheat the water such that a temperature of the water remains above aboiling temperature of the water at a standard atmospheric pressurewithout the water changing from a liquid state to a gaseous state for afirst time period sufficient for the core of the composite mat to reacha first target temperature; transmitting, by the processor, a thirdsignal to the one or more pairs of opposing hot-platens, receipt of thethird signal causing the one or more pairs of opposing hot-platens torelease the composite mat from the first pressure after the first timeperiod, wherein releasing the pressure on the composite mat causes thewater in the composite mat to change from a liquid state to a gaseousstate; and transmitting, by the processor, a fourth signal to a one ormore pairs of opposing cold-platens of the manufacturing apparatus,receipt of the fourth signal causing the one or more pairs of opposingcold-platens to compress and cool the composite mat for a second timeperiod sufficient for the core of the composite mat to reach a secondtarget temperature.

In accordance with some other aspects of the present disclosure, anon-transitory computer-readable storage medium storing executableinstructions that, when executed by one or more processors, cause theone or more processors to control a composite board manufacturingapparatus to produce a composite board comprised of plastic andcellulose is disclosed. The instructions may include instructions totransmit a first signal to one or more pairs of opposing hot-platens ofthe manufacturing apparatus heating and compressing a composite matcomprising plastic, cellulose, and water, the composite mat having acore at a midpoint between a first end and a distal end of the compositemat, receipt of the first signal causing the one or more pairs ofopposing hot-platens to heat and compress the composite mat atsubstantially a first pressure to superheat the water such that atemperature of the water remains above a boiling temperature of thewater at a standard atmospheric pressure without changing from a liquidstate to a gaseous state for a first time period sufficient for the coreof the composite mat to reach a first target temperature, wherein thewater changes into a gaseous state upon an expiration of the first timeperiod; and transmit a second signal to a pair of opposing cold-platensof the manufacturing apparatus, receipt of the second signal causing theone or more pairs of opposing cold-platens to compress and cool thecomposite mat for a second time period sufficient for the core of thecomposite mat to reach a second target temperature.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the following drawings and thedetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an example composite mat, in accordance with some embodimentsof the present disclosure.

FIG. 2 is a block diagram of a composite board manufacturing system, inaccordance with some embodiments of the present disclosure.

FIG. 3 is an illustration of a hot press compressing a composite mat, inaccordance with some embodiments of the present disclosure.

FIG. 4 is a flow diagram of an example process for forming a compositemat into a composite board, in accordance with some embodiments of thepresent disclosure.

FIG. 5 is a block diagram of a composite board manufacturing system, inaccordance with some embodiments of the present disclosure.

FIG. 6A is a block diagram illustrating a sequence of heating andcompressing a composite mat using a hot press in two stages, inaccordance with some embodiments of the present disclosure.

FIG. 6B is a block diagram illustrating a continuation of the sequenceof FIG. 6A in which the composite mat is cooled using a sudden coolingtechnique, in accordance with some embodiments of the presentdisclosure.

FIG. 7 is a flow diagram of an example process for forming a compositemat into a composite board using a sudden cooling technique, inaccordance with some embodiments of the present disclosure.

The foregoing and other features of the present disclosure will becomeapparent from the following description and appended claims, taken inconjunction with the accompanying drawings. Understanding that thesedrawings depict only several embodiments in accordance with thedisclosure and are therefore, not to be considered limiting of itsscope, the disclosure will be described with additional specificity anddetail through use of the accompanying drawings.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof. In the drawings,similar symbols typically identify similar components, unless contextdictates otherwise. The illustrative embodiments described in thedetailed description, drawings, and claims are not meant to be limiting.Other embodiments may be utilized, and other changes may be made,without departing from the spirit or scope of the subject matterpresented here. It will be readily understood that the aspects of thepresent disclosure, as generally described herein, and illustrated inthe figures, can be arranged, substituted, combined, and designed in awide variety of different configurations, all of which are explicitlycontemplated and made part of this disclosure.

Current solutions to reducing the amount of waste stored in landfills orincinerators often involve converting the waste into a useful product.For instance, in one example, the waste may be captured, melted, andcongealed between two solid materials (e.g., fiberglass or paper) into acomposite board comprising a mixture of the captured waste. If thecomposite board is properly melted and congealed, the composite boardmay be capable of being exposed to outdoor elements (e.g., sun, rain,snow, sleet, temperature changes, heat, cold, etc.) for prolonged timeperiods without any substantial deformations. Construction companies mayuse such composite boards to build roofing and/or side paneling forhouses or large buildings. Thus, instead of taking up space in landfillsthat are increasingly overflowing, waste may be manipulated bymanufacturers into a composite board that can benefit many differenttypes of consumers (e.g., homeowners, companies working in offices,warehouse owners, etc.).

Thermoplastic polymers are commonly used in the production of suchcomposite boards. In 2019, about 88.5 billion pounds of thermoplasticresin (polymers) were purchased in the United States. Most of this resinwas used in the production of various plastic articles. About 46 billionpounds of this resin was polyethylene in 2019. Processes that are usedto convert the polymers into commercial goods may include the steps of:

-   -   1. Heating the polymer;    -   2. Melting the polymer;    -   3. Forming the polymer into a desired shape and size;    -   4. Congealing (freezing) the polymer; and    -   5. Cooling the polymer.

Unfortunately, each of these steps may be relatively slow and energyintensive. Moreover, the large amount of energy required to makeproducts from thermoplastic polymers may place an additional burden onthe ecology of our planet.

Processing technologies that utilize thermoplastic polymers to formcomposite boards can include injection molding, extrusion,thermoforming, film-blowing, and others. These technologies may operatein a nearly anhydrous state.

Injection molding can utilize either thermoplastic or thermosettingpolymers. When applied to the former, it involves melting thermoplasticpolymers in a first step, and then injecting the molten polymer into amold (under high pressure) in a second step, and then cooling andsolidifying the polymer within the mold in a third step. The polymermight, or might not, be loaded with solid filler particles in theinjection-molded process. A heated barrel with either an internal ram orscrew may be used to convert thermoplastic pellets into a moltenpolymer. The barrel temperature of the injection molding equipment iscommonly in the range of about 300-700° F., depending on the polymertype that is being processed. Typically, the moisture content of thematerials being processed is very low. In many cases, the moisturecontent needs to be less than 0.1%. Excessive moisture can contribute topolymer degradation, as well as bubbles or streaks in the finished part.Molten material at the end of the barrel passes through a check valveand into a “shot” holding chamber. Typically, a “shot” of molten polymeris discharged rapidly (less than 1 second) at high-pressure into themold. The mold can exist as a wide array of different shapes and sizes.When applied to thermoplastics, the mold often includes a cooling jacketto facilitate faster cooling and solidification of the part.

Extrusion is a process in which a thermoplastic polymer is converted toa viscous, molten state and then extruded through a die to create acontinuous ribbon that has a particular shape and size. In many cases,the extruded part cools spontaneously without the aid of supplementalequipment. The extrusion temperature is set to ensure that the extrudedplastic is molten but is highly viscous. Substantial pressure isrequired to extrude the molten polymer, and although the extrudedplastic is initially molten, it is too viscous to undergo significantshape and size distortions immediately after being extruded from thedie. As the extruded part cools, the viscosity increases further.Eventually, the thermoplastic polymer congeals, and a stable part isachieved. In some cases, the solidified portion of the extruded part ismechanically pulled, and this version of the technology is commonlyreferred to as pultrusion. Equipment used to melt the polymer is similarto that used for injection molding. In many cases, the polymer is loadedwith fillers and/or other intractable solid particles. Wood-plasticcomposites (WPCs) are an example of a common commercial material that ismade by use of extrusion.

Thermoforming is a process in which a thermoplastic sheet is heated in afirst step to a temperature at which it is highly pliable. Heating iscommonly achieved by use of an oven. In a second step, the heatedplastic sheet is rapidly converted to a desired shape by use of molding,embossing, stretching, cutting, or a combination of these actions. Inmany cases, vacuum-forming is deployed in the second step.

There is a need for a manufacturing technology for the production ofcomposite boards that improves on existing molding, extrusion, andthermoforming technologies.

Manufacturing technologies for the production of thermoplastic compositeboards generally share processing steps that are common to those ofinjection molding, extrusion, and thermoforming. One sample process isdescribed in U.S. patent application Ser. No. 17/069,567, filed Oct. 13,2020, the entirety of which is incorporated by reference herein. Thisprocess generally involves forming a mat comprised of fragments. In somecases, the fragments are a mixture of discrete paper fragments and/orthermoplastic polymer fragments. In other cases, each fragment iscomprised of separate layers of paper and thermoplastic polymer. The matmay include paper/plastic fragments sandwiched between top and bottomlayers. These top and bottom layer may include paper, fiberglass, films,and/or other nonwovens or facer fabrics. Typically, thermoplasticadhesive layers are positioned between the paper/plastic fragment-basedcore and the top and bottom surface layers. The mat may be assembled ina relatively cold state and the component spatial order of thecomponents is mostly preserved throughout the subsequent thermalprocessing steps. The moisture content of the mat can range from about0-25%. The mat is first subjected to a hot-pressing step underconditions that compress the mat and melt a significant portion of thethermoplastic polymer, especially polyethylene. In a subsequent step,the hot mat may be subjected to a cold-pressing step under conditionsthat simultaneously maintain the compressed state of the mat and congeal(e.g., freeze) the molten thermoplastic in the mat.

The process described in U.S. patent application Ser. No. 17/069,567 maybe similar to common thermoplastic processing technologies to the extentthat it includes the steps of:

-   -   1. Heating the polymer;    -   2. Melting the polymer;    -   3. Forming the polymer to a desired shape and size;    -   4. Congealing (freezing) the polymer; and    -   5. Cooling the polymer.

However, the technology is quite different from the common thermoplasticprocessing technologies. For example, in some embodiments, panels aremade with the new technology using significant amounts of water. In somecases, the moisture content of the mat can be as high as about 25% justprior to thermal processing. The specific spatial arrangement ofcomponents in the new panel is established prior to thermal processingand may not be substantially altered by the thermal processing events.

It is also recognized that the new process shares some characteristicsthat are common to the process used to make wood-based panels. Ingeneral, wood-based panels are made by coating wooden elements withthermosetting adhesives, forming the treated wooden elements into a mat,and then consolidating the mat under conditions of heat and pressure.The moisture content of the wooden mat is usually in the range of about2-6%. The general spatial arrangement of the wooden elements in the matis preserved in the final wooden panel. In spite of these similarities,the wooden elements have different mechanical properties than themixture of paper and plastic fragments used in the new technology andthe thermosetting binder technology used in the production of wood-basedpanels is very different than the binder technology used in the newtechnology.

Common thermosetting binders used in the production of wood-based panelsinclude phenol-formaldehyde resoles, urea-formaldehyde resins, andpolymeric methylene diphenyl diisocyanate (pMDI). These thermosettingbinders may be converted from a liquid state to a load-bearingsolid-state at elevated temperature during the hot-pressing step. Oncethe thermosetting resin is converted to an intractable solid (thatcannot be melted), the wooden elements are bound together and generallyremain bound together without the need to rapidly cool the product.Thus, producers of wood-based panels generally attempt to heat the matas quickly as possible during the hot-pressing step in order to quicklycure the thermosetting binder. At the end of this process, wooden panelsmay be ejected from the hot-press and may not be subject to acold-pressing step (a combination of cooling and pressure). That said,some effort may be made to rapidly cool panels made withurea-formaldehyde resin. The purpose of rapidly cooling theurea-formaldehyde based panel is to ensure that the curedurea-formaldehyde does not thermally degrade. Pressure is not applied tothe urea-formaldehyde based wooden panels during cooling (becauseapplication of pressure is not needed in order to maintain the size andshape of the panel after pressing). Manufacturers of wood-basedcomposites may not be motivated to limit the amount of heating in orderto more rapidly cool the panel. Wood-based panels, especially those whoutilize phenol-formaldehyde resin or pMDI, may deliberately post-heatthe panels through hot-stacking after the hot-pressing step in order tomore extensively cure the resin and to thermally modify the wood tissuein a manner that improves its water-resistance.

In contrast to the process used to manufacture wood-based composites,the embodiments described herein may be associated with a motivation tofirst heat the mat as quickly as possible, but then to immediately coolthe mat as quickly as possible while maintaining pressure on the mat inorder to achieve a particular caliper (thickness value) in the finishedpanel. For the sake of achieving maximum processing speed, it can bebeneficial to minimize the cumulative time required for both the heatingevent and the cooling event (under pressure). This particularcombination of dynamics is different than that associated with injectionmolding, extrusion, thermoforming, or the production of wood-basedcomposites.

As previously stated, the moisture content of wooden mats used in thecommercial production of wood-based panels that are made withthermosetting adhesives may be limited to a maximum of about 6-8%. Whenthe moisture content of the wooden mat is greater than this, the steampressure inside of the mat that develops as the mat is being hot-pressedbecomes greater than the strength of the mat. Under these conditions,the mat ruptures, sometimes explosively, when the hot-press opens at theend of the pressing cycle. This event is commonly known as a“steam-blow.” Panels that experience steam-blows contain localized shapedefects that are easily detected in the quality control process. Panelswith steam-blows are rejected and are thus financially detrimental.

It is common for wood-based panels, including laminated veneer lumber(LVL), oriented strand board (OSB), medium density fiberboard (MDF), andparticleboard (PB) to be made using hot-presses that are“position-controlled”. This type of press includes sensors that detectthe distance between the top and bottom platen and a control system thatcontinuously adjusts the pressure exerted on the mat to ensure that aparticular mat thickness is achieved during the pressing cycle. As anexample, a position-controlled press system might specify that a matwill be pressed to a thickness of 0.438 inches for most or all of thepressing event. Hot-presses with this type of control system commonlyexert about 600-1,500 psi of pressure on the mat during the initialstages of pressing in order to rapidly compress the mat to a thicknessthat is equal to or similar to the thickness of the final panel.

Wood is a visco-elastic material. When a wooden object is exposed to amechanical stress, such as pressure, the object will deform (e.g., bendor compress or twist). Under some environmental conditions and stresslevels, the deformation (e.g., strain) in the wooden object will bewholly or partially eliminated when the stress on the wooden object isdiscontinued. This is the “elastic” behavior of the wood. Likewise,under some environmental conditions and stress levels, the deformation(e.g., strain) in the wooden object will be wholly or partially retainedwhen the stress on the wooden object is discontinued. The degree of thispermanent deformation is typically dependent on both the level of thestress and the duration of the stress on the wooden object. This is the“viscous” behavior of the wood. Materials that exhibit both viscous andelastic properties are known as visco-elastic materials.

When wooden mats are being pressed in a position-controlled press,especially at elevated temperature, the mat undergoes some level ofpermanent deformation during hot pressing. Thus, it exhibits some levelof “viscous” behavior. As the mat deforms, the pressure that is requiredto maintain the targeted thickness of the mat decreases. For instance,the pressure that is exerted by the press on the wooden mat in thebeginning of the press cycle in order to achieve a particular targetedmat thickness can be as high as about 600-1,500 psi. In contrast, by theend of the hot-pressing cycle, the pressure exerted on the mat istypically reduced to only about 20-60 psi.

Platen temperatures that are commonly used in the production ofwood-based panels range from about 340-430° F. Thus, as mats aresubjected to hot-pressing, water in the mat is generally heated to atemperature that exceeds 212° F., which is the boiling point of water at1 standard atmosphere of pressure. A first portion of the water thatexceeds this temperature will be converted to steam (gas) and will leakout of the compressed mat through gaps and pores in the mat structure. Asecond portion of the water that exceeds a temperature of 212° F. willremain trapped in the mat under pressure. It is this second portion ofwater in the mat that contributes to the potential for steam-blows.Fortunately, at the end of the wooden panel hot-pressing cycle, themoisture content is typically less than 1-2%, and the thermosettingresins can provide significant internal bond strength between the woodenelements, even when the mat is hot (300-420° F.), in order to prevent asteam-blow. Thus, the wood panels industry has learned that some amountof moisture can be tolerated in the wooden mat (typically less thanabout 6-8%) prior to pressing without experiencing a steam-blow at theend of the hot-pressing process.

In contrast, the disclosed embodiments can operate with initial matmoisture content levels as high as about 25%. Platen temperatures usedin exemplary processes can range from about 310-450° F. Thus,substantial amounts of steam can be generated by hot-pressingpaper/plastic fragment mats with a moisture content greater than about6-8%. In order to avoid destructive steam-blows, venting cycles areintroduced into the hot-pressing schedule in the exemplary processeswhen the moisture content of the mat exceeds about 6-8%. Like wood, thepaper/plastic fragments exhibit some level of elastic response toexternally applied pressure. Thus, as the press opens momentarily for aventing event, the mat expands to some degree. Since the binder in thedisclosed embodiments is a thermoplastic polymer, the bonds betweenpaper elements are immediately reestablished as the press closes afterthe venting cycle. If such venting events were attempted in theproduction of a wood-based panel, the mat expansion would easily breakthe fragile, partially formed bonds associated with the thermosettingresin. Thermosetting resin bonds are typically very weak while they arein a partially cured state.

It follows that a first portion of the water in the paper/plasticfragment mat processed according to the disclosed embodiments isconverted to steam (e.g., gas) and leaks out of the sides of the matwhile the hot-press is closed or is emitted from the mat while the pressis open during venting cycles. A second portion of the water in thepaper/plastic fragment mat can exist under pressure in a superheated,liquid state. Most commonly, a core temperature of about 260-300° F. isdesired and targeted at the end of the hot-pressing event in order toensure that a high percentage of the polyethylene in the paper/plasticfragment mat has melted. Achieving a core temperature in the mat of 300°F. is highly desirable and, under typical commercial processingconditions, is almost always coincident with the elimination ofessentially all of the water in the mat.

Under typical processing conditions in the disclosed embodiments, whenthe hot-press opens at the end of the hot-pressing cycle, there is noimmediate decrease in the core temperature of the mat. In fact, athermal gradient typically exists in the mat at the end of thehot-pressing event. Thus, the mat is cooler in the core layer and warmerin the surface layer, which has been in direct contact with thehot-platens. The existence of this thermal gradient results in acondition in which the core layer of the mat actually continues toincrease in temperature for some time period after the mat has exitedthe hot-press and even entered the cold press. This behavior isundesirable because it retards the rate of cooling of the mat in thecold press. Generally, the mat may be cold pressed for a time periodsufficient to cool the core layer of the mat to a targeted coretemperature (e.g., 195° F.). The core temperature at the end ofcold-pressing needs to be sufficiently low to congeal (e.g., freeze) allor most of the molten plastic (commonly polyethylene) in the core layerof paper/plastic fragments. Insufficient cooling under pressure canresult in panels having lower strength values. It can also result incaliper values that are greater than that which is targeted orspecified. Unfortunately, long cold-pressing periods, which aregenerally required in order to meet the quality control targets, areeconomically detrimental.

Thus, there is a need for embodiments that allow for reducedcold-pressing time while simultaneously achieving the core temperaturetargets at the end of both the hot-pressing event as well as the end ofthe cold-pressing event.

The disclosed embodiments described herein provide new and improvedmethods for producing panels from mixtures of paper fragments andplastic fragments, or alternatively, from fragments comprised of bothpaper and plastic layers. These methods may include the following steps.First, a mat may be formed that includes 1) a heat-resistant bottomfacer; 2) a core layer comprised of either a mixture of paper fragmentsand plastic fragments, or alternatively, fragments comprised of bothpaper layers and plastic layers; and 3) a heat-resistant top facer.Optionally, the mat further includes adhesive layers (thermoplastic orthermosetting) between the outer facers and the core layer. The corelayer may have an initial moisture content of about 3-25% prior tohot-pressing.

Second, the mat may be pressed between hot-platens (surface temperatureequal to about 310-450° F.). The initial pressure on the mat can rangefrom about 10-1,500 psi. Venting cycles, in which the press opens forbrief periods of time (1-3 seconds) can optionally be used in theinitial and middle stages of the hot-pressing schedule. Thereafter, apressure of about 25 psi or greater may be maintained on the mat for theduration of the hot-pressing step such that at the end of thehot-pressing step the moisture content of the mat is in a predeterminedrange of about 0.5-4.0% (most preferably about 1.5-4.0%) and the coretemperature of the mat is in the range of about 260-340° F.

Then, the hot-press is opened such that the pressure on the hot-mat isreduced to about 0-5 psi (most preferably about 0 psi) for a period ofabout 0.5 seconds or longer. Next, the hot mat is immediately pressedbetween cold-platens (surface temperature less than about 120° F.). Thepressure exerted on the mat during cold pressing will generally be inthe range of about 5-40 psi and will be sufficient to achieve a panel ata particular targeted caliper (thickness) at the end of thecold-pressing step. The duration of the cold pressing step willgenerally be dependent on the thickness of the mat as well as otherparameters and will be sufficient to congeal all or most of the plasticin the core layer.

Following the described sequence of steps, a sudden and dramaticdecrease in core temperature spontaneously occurs in the mat after thehot-pressing step. This rapid temperature drop helps to reduce the timerequired for the cold-pressing step.

The paper and plastic fragments suitable for the disclosed embodimentscan be isolated from municipal solid waste, recycling streams or otherwaste streams. Alternatively, they can be isolated from un-usedmaterials. Preferred fragments have a thickness ranging from about0.001-0.100″, a width of about 0.1-3.0″, and a height of about 0.1-3.0″.The shape of the fragments could be rectangular, circular, irregular, orsome other shape. Paper and plastic fragments can be obtained byprocessing larger sections of paper and larger sections of plasticthrough shredders, mills, or other machines that are designed todisintegrate relatively large objects into relatively small objects.Most machines of this sort have a chamber that contains moving knives,blades or other cutting tools as well as counter knives or otherstationary objects that are positioned in close proximity to the path ofthe moving blades or knives. Materials to be disintegrated aretransferred into the compartment at an acceptable feed rate. Typically,a portion of the wall of the compartment includes a screen that has adeliberately selected mesh size. As objects inside of the compartmentare reduced in size, they eventually pass through the screen and arethen transferred to the next processing center.

Paper fragments can have a moisture content ranging from about 0.1-50%.Plastic fragments will generally have a moisture content of about 0-3%.A dominant component in the plastic will be polymer. Typically, polymermay constitute about 50-100% of the plastic. Polymer types will include,but are not limited to, polyethylene (high density, medium density, andlow density), polypropylene (especially isotactic), copolymers ofethylene and propylene, polyesters (including polycarbonate,polyethylene terephthalate and polybutylene terephthalate), polystyrene,polyvinyl chloride and polymers based on acrylonitrile (including AN,ABS and PMMA). Polymers used in plastics can also be based on rubberymonomers such as butadiene or isoprene. Other polymers, such as SBR, canbe based on mixtures of rubbery monomers (butadiene) and hard monomers(styrene). Polyethylene is a highly preferred polymer for thisdisclosure. Many plastics include plasticizers in addition to thepolymer resin. Examples of plasticizers include dioctyl phthalate orbenzyl butyl phthalate. Plasticizer levels in plastics can range fromabout 0-40% by weight. Some plastics, including polyvinyl chloride,could have plasticizer levels even greater than 40%. Plastics can alsoinclude colorants (dyes and/or pigments), opacifying agents, opticalbrighteners, preservatives, fillers, and other additives. In someembodiments, plastic may be any plastic that melts within a temperaturerange of about 70-400° F. and may include polyethylene, polypropylene,copolymers of ethylene and propylene, polymers of ethylene and vinylacetate, polystyrene, acrylic polymers, polymers based of styrene andbutadiene, etc.

In some cases, individual fragments are comprised of both paper andplastic. For example, fragments can be made by grinding a beveragecarton (e.g., Tetra Pak′) type packaging for liquid beverages. This typeof packaging includes continuous paper layers, polyethylene layers, andaluminum foil layers. The level of polyethylene used in these cartons isrelatively low (20-30%), but it is distributed continuously anduniformly on the paper. Thus, the distribution of polyethylene on thepaper is essentially perfectly optimized. In some cases, this type offragment might also work well for the purpose of this disclosure,although the plastic level is typically less than 40% by mass.

The basis weight of the paper/plastic fragments in the mat can rangefrom about 0.2-5.0 lb/ft². Preferred basis weight values are about1.7-2.5 lb/ft². Heat-resistant facers include fiberglass fabrics, paper,and films or nonwovens based on polymers, including nylon and polyester,which have melting points in excess of about 420° F.

Adhesive layers can be positioned between the facer and core layers.Suitable adhesive layers include thermoplastic films comprised ofpolyethylene, polypropylene, ethylene acrylic acid copolymers, andethylene vinyl acetate copolymers. Acceptable copolymers can also bebased on ethylene and propylene. Alternatively, the adhesive layer canbe comprised of films based on thermosetting resins that have beensolidified, but not fully cured. Such films can be based onphenol-formaldehyde or melamine-formaldehyde resins. Said films canexist as resin only, or in other cases, paper can be coated on bothsides with said resins. Further yet, adhesive layers can be prepared byspray-application of aqueous acrylic, styrene-butadiene, or polyvinylacetate aqueous latex adhesives.

Hot presses suitable for this disclosure include continuous presses,single-opening presses, and multi-opening presses. Control systems caninclude those that are pressure-controlled or position-controlled.Highly preferred control systems have the ability to establish matthickness targets in the first portion of the hot-pressing event andthen to control for mat pressure targets in the later stages of thehot-pressing event. Press control systems that operate on aposition-control basis only are less desirable, because this type ofpress might not be able to maintain a pressure on the mat of at least 25psi for the entire duration of the hot-pressing event.

Relatively little systematized information is available regarding theability of a mat (either wooden or comprised of paper/plastic fragments)to retain steam or superheated water during hot-pressing. The ability toretain steam or water is important to achieve the desired sudden coolingeffect at the end of hot-pressing, which is a key benefit. In general,it appears that in order to heat the core layer of the mat to atemperature of about 260-340° F. and simultaneously trap the properamount of water in the mat, the mat needs to contain absorbent particles(paper fragments) and it needs to be relatively non-porous. In anexemplary embodiment, higher levels of molten plastic and higherpressing pressures at the end of the hot-pressing event help to reducethe porosity of the mat during the latter stages of hot pressing.

At the end of the hot-pressing event, the pressure on the mat is reducedto about 0-5 psi. Most preferably, the hot-press is opened at the end ofthe hot-pressing event, which eliminates the applied pressure on the matfor a period of at least 0.5 seconds. Under this condition, thesuperheated liquid water in the mat may be instantaneously converted tosteam. In fact, an emission of steam from the mat can be clearlyobserved at the end of the hot-pressing event when panels are made inaccordance with this disclosure. This phase change requires about 2,258Joules of energy per gram of water. This energy may substantiallyspontaneously dissipate from the portion of the mat that includes paper,plastic, and non-superheated water. The superheated water within the matmay be partially or wholly ejected from the mat and the loss of energyfrom the paper, plastic, and non-superheated water portion of the matmay result in a temperature decrease for the portion of the mat thatremains in the press. In some cases, an initial temperature decrease atthe center of the mat can be as high as about 40-60° F. For example, ata temperature of 300° F., a mat comprised predominantly of a mixture ofpaper and polyethylene has a specific heat capacity of about 1 J/g/F.Thus, removing 1 J/g of energy may result in a temperature decrease ofabout 1° F. If 2% of the mat, by mass, is superheated water at the endof the hot-pressing cycle, and all of this superheated water isimmediately converted to steam, which may be emitted from the panel,then the expected temperature decrease would be about 45.2° F.

${\Delta T} = \frac{(0.02)\left( {2258\frac{J}{g}} \right)}{1.\frac{J}{gF}}$

Thus, the degree of the instantaneous temperature decrease may beproportional to the amount of superheated water that can be retained inthe mat at the end of the pressing cycle.

In general, the maximum amount of superheated water that can be retainedin the mat without causing a steam-blow is expected to be related to theamount of plastic in the mat, the temperature of the mat at the end ofthe hot-pressing cycle, the speed at which the pressure on the mat isrelieved, and possibly other factors. In an exemplary embodiment, themaximum amount of superheated water that can be retained in the mat atthe end of the hot-pressing event without resulting in a steam-blow isabout 3%. In other embodiments, the maximum amount of superheated waterthat can be retained is 5%.

Superheated water has a temperature greater than 212° F. but exists in aliquid state. It is known that external pressure is required to createsuperheated water. For instance, a gauge pressure of about 53 psi isrequired in order to achieve a water boiling point of 300° F. Further, agauge pressure of about 105 psi is required in order to achieve a waterboiling point of 340° F. Unfortunately, information regarding therelationship between temperature, gauge pressure, and water vaporpressure in a mat comprised of paper fragments, water, and plasticfragments is not known. A high percentage of water in a mat can bepreserved, even up to temperatures as high as about 340° F., byapplication of about 25-50 psi hot-pressing pressure, especially whenthe core temperature of the mat has a temperature in the range of about212-340° F. This result is somewhat unexpected. It could not bepredicted from the established relationships between water boiling pointand pressure, and it is different than the behavior of water in woodenmats during hot-pressing using conventional position-controlled presssystems.

In a preferred embodiment, the initial moisture content of the mat(prior to hot-pressing) is about 4-6%. The mat may have a coretemperature at a midpoint between a distal and a proximal end of themat. As the core temperature of the mat exceeds about 212° F. during thehot-pressing event (using platens with a surface temperature in therange of about 350-450° F.), the pressure exerted on the mat through theplatens is maintained in the range of about 25-50 psi until the targetcore temperature is reached. Ideally, the target core temperature willbe in the range of about 260-340° F. When the target core temperature isattained, the pressure on the mat may be mostly or completely relievedfor a period of about 0.5 seconds or longer. Preferred levels ofpressure on the mat during this relief-period range from about 0-5 psi.Ideally, the panel should be removed from the hot-press immediatelyduring or after the pressure-relief event.

When mats have an initial moisture content of about 5% or higher and arebeing processed according to the described embodiments with a hot-platentemperature in the range of about 380-450° F., the core temperature ofthe mat will increase at a rate of about 0.65-1.5° F. per second betweena core temperature of about 212-260° F. when the pressure applied to themat at this point in the hot-pressing event is in the range of about25-50 psi. When lower pressures are used in this portion of thehot-pressing schedule, liquid water in the mat is converted to steam,which steadily leaks from the edges of the mat at a rate thatessentially depletes the mat from water by the time that the target coretemperature is reached. This adverse condition can be detected byinspecting the rate of temperature increase in the core of the mat overthe temperature range of about 212-260° F. Specifically, the rate oftemperature increase will be about 0.2-0.7° F. per second wheninsufficient mat pressure is being applied. The slow rate of temperatureincrease is largely due to substantial amounts of thermal energy fromthe hot-press being diverted to evaporation of the water.

The use of higher levels of polyethylene tends to promote improvedbonding between the paper fragments and might also contribute to betterretention of superheated water in the mat during the later stages ofpressing. Unfortunately, elevated levels of polyethylene in the mat alsocontribute to the viscous nature of the mat (as opposed to “elastic”).In a position-controlled hot-press, which is commonly used in thewood-based panels industry, the level of pressure exerted on the panelin the later stages of the hot-pressing cycle become extremely low, evenapproaching zero psi, for mats that are highly viscous. As justdiscussed, the low pressure at the end of the hot-pressing cycle resultsin dehydration of the mat. This dilemma can be resolved through theunconventional use of a pressure-controlled hot-press. The viscousnature of the mat in the later stages of hot-pressing results in thepotential for excessive compression of the mat. Thus, the disclosedembodiments require the use of relatively low pressures during theinitial stages of hot pressing and relatively high pressures (but nottoo high) during the later stages of hot-pressing, as compared to thepressure schedule that would be experienced using a conventionalposition-controlled press system. There are no literature references,textbooks, patents, or other prior art that teach this adaptive courseof process development.

When panels are being manufactured using the disclosed embodiments on acontinuous press that includes a heating zone and a cooling zone, a gapmay be designed into the press between the heating and cooling zones inorder to create a mechanism to briefly reduce the external pressure thatis exerted on the press immediately after hot-pressing.

Suitable cold presses include continuous presses, single-openingpresses, and multi-opening presses. Control systems can include thosethat are both pressure-controlled or position-controlled. Preferredcontrol systems for the cold press are position-controlled. Calipervalues specified in a position-controlled system may be equal to thetargeted thickness of the resulting panel. Alternatively, the calipervalue specified can be about 0.001-0.015 inches less than the targetedthickness of the resulting panel in anticipation of some modest level of“spring-back” when the panel exits the cold press. Pressure-controlledsystems can also be used in the cold press. When pressure-controlledsystems are used, operators may empirically determine pressure valuesthat will achieve the targeted panel thickness. In general, pressuresexerted on the mat during cold pressing are expected to be in the rangeof about 5-40 psi.

In most cases, cold presses will include coiled tubes that circulatecooling fluid through the top and bottom platens. The cooling fluid canbe water, glycol/water mixtures, or oils. Typically, the cooling fluidis pumped through the platens and circulated back to a chiller orrefrigeration unit, such as those made by Mokon of Buffalo, NY. Ingeneral, the chiller should be adjusted to achieve a platen surfacetemperature of about 20-90° F. Most preferably, the chiller should beadjusted to achieve a platen surface temperature of about 35-60° F. Ingeneral, colder platen surface temperature values will allow for fastermat cooling rates. However, operating with chiller temperatures that areless than 32° F. can result in the accumulation of ice, which canpresent processing complications.

In general, mats need to be cold-pressed for a time period that issufficient to cause the plastic in the mat that became molten in thehot-pressing event to congeal (e.g., freeze) during the cold-pressingevent. When polyethylene is used in the mat as the primary binder, thenthe core of the mat should be cooled to a temperature of about 190-200°F. during the cold-pressing event. Panels can be made with cold-pressingtimes that are associated with higher core temperature values as the matexits the cold-press, but the resulting panels will potentially havelower strength and greater variance in caliper. The time required toachieve sufficient cooling will be dependent upon the thickness of themat, the density of the mat, the composition of the mat, and thetemperature of the cold press platens. The time required to achievesufficient cooling will also depend upon the temperature of the matafter hot-pressing.

The described embodiments result in the following surprising andunexpected benefits. Heating the mat to a temperature of 260-340° F.without evaporating all of the water in the mat results in shorterhot-pressing periods that are required to reach core temperature targetsthan that which would be experienced if all of the water in the mat wasbeing evaporated during hot-pressing. Rapidly lowering the mattemperature immediately after hot-pressing results in shortercold-pressing periods that are required to reach core temperaturetargets during cold-pressing. These very important and dramaticimprovements in processing rate are achieved without the need for harshchemicals or extreme processing conditions.

Referring now to FIG. 1 , an example composite board 100 is shown, inaccordance with some embodiments of the present disclosure. Compositeboard 100 may be manufactured to operate as a roof cover board that canprovide impact protection (from hail, foot traffic, and/or heavyequipment), temporary water resistance, fire resistance, wind-upliftconstraint, thermal dimensional stability, and/or flexibility that isoften required in roofing applications. Composite board 100 may bemanufactured to be receptive to adhesives and/or mechanical fasteners.

Composite board 100 may comprise three discrete layers, a top surfacelayer 102, a bottom surface layer 104, and a core layer 106. Top surfacelayer 102 may be about 0.005-0.050″ thick and may comprise of eitherpaper or a fiberglass web. Bottom surface layer 104 may be about0.005-0.100″ thick and may comprise of paper, a fiberglass web, nylonfilm, polyester film, cellulose acetate film, nylon or polyesternon-woven fabrics, and/or textiles, such as those based on cotton. Corelayer 106 may be about 0.100-1.500″ thick and comprise discrete paperfragments and plastic fragments such as polypropylene or polyethylenefragments, which may be connected through the use of a thermoplasticbonding resin, including polyethylene.

The bonding resin may be attached in a random pattern to less than 100%of the paper fragment and polypropylene fragment surface area. The paperfragments may be shaped as irregular plates with a diameter of about0.050-2.000″ and a thickness of about 0.005-0.050″. The polypropylenefragments can have multiple shape types, some of which are irregular. Insome embodiments, the largest dimension of the polypropylene fragmentsmay be about 2.000″, while the smallest dimension may be about 0.050″.The thickness axis of the paper fragments may be generally orientedorthogonally to the plane of the board article. The two differentfragment types may be uniformly distributed in the core layer relativeto each other. The level of paper fragments in the core layer may beabout 30-70% on a mass basis. The level of polypropylene fragments inthe core layer may be about 5-30%. The level of thermoplastic bondingresin in the core layer may be about 10-60%. The density of the corelayer can be about 35-70 pcf. Thus, the core layer may include smallvoids in and around the particles, which could improve flexibility. Thecore layer may be attached to the top and bottom surface layers by useof a thermoplastic adhesive, including polyethylene or polypropylene.

The structure of composite board 100 may be designed to achievecompression load support, sudden impact resistance, wind upliftresistance, fastener retention, adhesive compatibility, temporary rainprotection, low flame spread, thermal dimensional stability, and anexceptional level of mechanical flexibility. The design promotes rapidand easy installation of the cover board in a commercial low slope roofapplication. It may be especially advantageous in re-roofingapplications due to its level of flexibility, which may allow it to moreeasily conform to the curved contour of the perimeter region of theroof. The top major surface may allow for the absorption of adhesivesbut may temporarily resist transfer of rainwater into the core layer ofthe board.

Referring now to FIG. 2 , a block diagram of a composite matmanufacturing system 200 is shown, in accordance with some embodimentsof the present disclosure. Composite mat manufacturing system 200 mayinclude a manufacturing apparatus 202 and a composite mat 204. Compositemat 204 may be similar to composite board 100, shown and described withreference to FIG. 1 . As illustrated, composite mat 204 may be fed intodifferent stages of manufacturing apparatus 202. Such stages may includea mat formation assembly stage 206, a hot press 208, and a cold press210. Manufacturing apparatus 202 may be configured to move composite mat204 between the different stages via a conveyor belt assembly 212 toform a composite board. For example, using a conveyor belt, conveyorbelt assembly 212 may move composite mat 204 from mat formation assemblystage 206 to hot press 208 and then to cold press 210. Conveyor beltassembly 212 may output composite mat 204 as a composite board aftercomposite mat 204 is cooled and its contents congealed in cold press210. Once cooled, composite mat 204 may be a composite board that can beused for various roofing and/or siding applications.

Before composite mat 204 can be provided to manufacturing apparatus 202,the materials to create composite mat 204 may be created. For example,fragments of paper and polypropylene may be generated by feedingrelatively large sheets of paper and relatively large articles ofpolypropylene into a mill, which may mechanically disintegrate the paperand polypropylene into fragments. The mill may be equipped with a screenthat has a mesh size of about 1″. Thus, paper fragments andpolypropylene fragments that are being processed inside of the mill maycontinue to be reduced in size until they are able to pass through thescreen. In this manner, fragments may be generated that have a size ofabout 1″ or less. If desired, a smaller or larger mesh size could beused to yield smaller or larger fragments. Optionally, thermoplasticadhesive could be processed through the mill as well. Different millscould be used for each of the fragment types or they could be processedtogether through the same mill. When a single mill is used, there may bea tendency for the three components to be mixed together. Additionalmixing can be achieved by processing the components through a secondaryblender. The secondary blender may allow for the convenient applicationof additional adhesives and/or other functional additives. The secondaryblender may be especially beneficial for the introduction of liquidadditives or additives that need to be uniformly distributed within thecore furnish. Optionally, the paper fragments only or the mixture ofpaper fragments and polypropylene fragments can be processed through adryer prior to the secondary blender. The blended core furnish may thenbe conveyed to mat formation assembly stage 206.

A mat formation assembly stage 206 may comprise a wooden or plasticplatform on which composite mats may be created by various mechanicaldevices. For instance, on mat formation assembly stage 206, a bottomlayer fabric (4″ wide or greater) may be unwound onto a horizontalconveyor belt of conveyor belt assembly 212, which may convey the bottomlayer fabric in a forward direction. An adhesive may be applied to thetop side of the bottom layer fabric. The adhesive could exist as a filmor it could be a liquid, which could be applied as a spray, or acurtain, or it could be flood coated. Alternatively, the adhesive couldbe a thermoplastic that is applied to the bottom layer fabric in anextrusion process. The blended core furnish may be deposited on top ofthe previously applied adhesive. The basis weight of the core furnishmay be about 1.5-2.5 lb/ft². Rakes or other devices can be used toensure that the deposited core furnish is uniformly distributed at thetargeted basis weight. More adhesive may be applied to the top side ofcomposite mat 204. A top layer fabric (48″ wide or greater) may beunrolled and positioned over the adhesive that was previously applied tocomposite mat 204. In some cases, the resulting layered assembly will beprocessed through opposing rolls in order to compact it.

Composite mat 204 may then be conveyed into hot press 208. Hot press 208may comprise two hot-platens that are spaced apart and may be configuredto move towards each other to exert pressure on composite mats that arepositioned between the platens. The two hot-platens may be heated usingvarious heating methods (e.g., via electricity, which can power heatingelements, or use of circulating hot oil, which can be heated bycombustion of natural gas or other fuels). The hot-platens may each beheated to have a surface temperature between about 320-450° F. Hot press208 may be configured to exert a pressure of about 20-800 lb/in² oncomposite mat 204 for a period of about 2-10 minutes as conveyor beltassembly 212 moves composite mat 204 between the stages of manufacturingapparatus 202. The applied pressure may be constant. By applying suchpressure, hot press 208 may cause the thickness of composite mat 204 todecrease. However, in some embodiments, the hot press 208 may beconfigured to hold the thickness of composite mat 204 to a constantvalue. To do so, hot press 208 may initially apply a relatively highpressure to composite mat 204, such as 600-800 psi, and graduallydecrease the applied pressure to about 50 psi, or even lower, as thepressing event continues. In some embodiments, hot press 208 may applypressure in two stages. In a first stage, hot press 208 may applypressure using a position-controlled method to form a composite mat to adesired thickness (e.g., a target thickness). In a second stage, hotpress 208 may maintain a constant predetermined pressure on compositemat 204.

In general, the gap between the top and bottom platens during pressingcan be in the range of about 0.25-1.00″. In one example, a preferred gapbetween the platens is about 0.50″ when the basis weight of the corefurnish in the assembly is about 1.8-2.4 lb/ft². If the moisture contentof composite mat 204 is greater than about 4-5%, then venting cyclesmight be needed during the hot-pressing process. Upon exiting hot press208, conveyor belt assembly 212 may move composite mat 204 through atransition phase in which composite mat 204 is not heated, cooled, orcompressed for a short time period. The composite mat would thereafterbe immediately transferred into cold press 210.

In cold press 210, the hot, compacted composite mat 204 may be processedto freeze or congeal the thermoplastic components of composite mat 204.Cold press 210 may comprise two cold-platens that are spaced apart andmay be configured to move towards each other to exert pressure to cooland shape composite mats that are positioned between the platens. Thetwo cold-platens may be cooled using conventional cooling methods (e.g.,cooling fluids being circulated through chillers or similarrefrigeration devices). The two cold-platens may be configured to havetop and/or bottom platen surface temperature values of about 30-80° F.The pressure in the cold press may be maintained at about 5-25 psi. Thegap between the platens may be equal to a stored target thickness forthe resulting board. The cold press time may be about 2-10 minutes,which may be sufficient to cool composite mat 204 throughout itsthickness to a temperature of less than about 190° F. In someembodiments, composite mat 204 may be cooled to a temperature of lessthan about 110° F. prior to exiting cold press 210.

Subsequent to cold pressing, composite mat 204 can be cut into boards,such as boards having a dimension of 4′ wide x 8′ long, which may beuseful for a roof cover board application. Boards can be stacked,treated with edge sealant, banded, and packaged. Composite matcompositions and methods of forming such composite mats are furtherdescribed in U.S. patent application Ser. No. 17/069,567.

In some embodiments, composite mat manufacturing system 200 may includesensors 214. Sensors 214 may include depth sensors, pressure sensors(e.g., pressure transducers), temperature sensors, moisture sensors, orany other type of sensors. Sensors 214 may be coupled to manufacturingapparatus 202 at any location. Sensors 214 may be configured to detectdata about composite mats as such mats maneuver around composite matmanufacturing system 200 and/or before composite are compressed by hotpress 208. Sensors 214 may detect data about the mats and transmit thedata to a controller. As will be described below, the controller mayreceive the data and control hot press 208, cold press 210, and/orconveyor belt assembly 212, based on the data to ensure the respectivecomposite mat is properly heated and cooled.

Referring now to FIG. 3 , a block diagram illustrating a hot press 302compressing a composite mat 304 is shown, in accordance with someembodiments of the present disclosure. Hot press 302 may includehot-platens 306 and 308 as an opposing pair of hot platens. Hot press302 may include any number of opposing pairs of hot platens. Hot press302 may be operated by a controller (not shown) that is configured tocause hot-platens 306 and 308 to heat up and close in on each other toapply pressure and heat composite mat 304. The controller may cause hotpress 302 to apply pressure and/or heat composite mat 304 for apredetermined amount of time. In some embodiments, the controller maydetect when the predetermined amount of time is over and movehot-platens 306 and 308 further apart to release composite mat 304 socomposite mat 304 may be removed from hot press 302. Alternatively, insome embodiments, the controller may be configured to move composite mat304 along a conveyor belt at a rate that causes composite mat 304 to becompressed and heated for the predetermined amount of time beforecomposite mat 304 exits hot press 302. In such embodiments, hot-platens306 and 308 may remain on and heated as composite mats are pushedthrough hot press 302 via the conveyor belt. Although not shown, thecontroller may similarly control a cold press including any number ofpairs of opposing cold platens to cool and/or shape composite mat 304for a predetermined amount of time, in some cases after hot press 302heats composite mat 304.

Referring now to FIG. 4 , a flow diagram of an example process 400 forforming a composite mat into a composite board is shown, in accordancewith some embodiments of the present disclosure. Process 400 can beperformed using a manufacturing apparatus (e.g., manufacturing apparatus202). Process 400 may include more or fewer operations and theoperations may be performed in any order. Performance of process 400 mayenable the manufacturing apparatus to manufacture, from waste materials,a composite board that can be used for roofing and/or siding.

An operation 402 may include forming a composite mat using paper andplastic fragments. The paper and plastic fragments may be created bysending paper and plastic material through a shredder. The paper andplastic fragments may be placed between two solid surfaces (e.g.,plexiglass and/or paper) and placed onto a horizontal conveyor belt ofthe manufacturing apparatus. For example, a bottom layer fabric may beunwound onto the conveyor belt, which may convey the bottom layer fabricin a forward direction. An adhesive may be applied to the top side ofthe bottom layer fabric. The blended core furnish comprising the paperand plastic fragments may be deposited on top of the applied adhesive.Rakes or other devices can be used to ensure that the deposited corefurnish is uniformly distributed at the targeted basis weight. Moreadhesive may be applied to the top side of the core furnish. A top layerfabric may be unrolled and positioned over the adhesive on the top sideof the core furnish.

At an operation 404, the composite mat may be conveyed into a hot pressof the manufacturing apparatus and the hot press may press a pair ofhot-platens to compress and heat the composite mat for a hot press time.The hot press may be configured to exert a predetermined amount ofpressure on the composite mat as a conveyor belt of the manufacturingapparatus moves the composite mat through the hot press. In someembodiments, the manufacturing apparatus may not include a conveyorbelt, and may instead include an opening into which a user may insertthe composite mat. The hot press may compress and heat the composite matfor a predetermined amount of time (e.g., based either on the length ofthe hot-platens and speed of the conveyor belt carrying the compositemat, or a time determined based on the characteristics of the compositemat). The time may be stored in memory of a device or controller that isoperating the manufacturing apparatus and may correspond to differentmat compositions and/or thicknesses. For example, different matcompositions and/or thicknesses and corresponding times in which theyneed to be heated to reach a target core temperature may be stored inmemory. The controller may receive data (either from sensors or via auser input) and compare the data to the different mat compositionsand/or thicknesses in memory using a look-up table. The controller mayidentify the times that match the mat compositions and/or thicknessesand control a conveyor belt to heat the mat for the time or to otherwiserelease the mat after the time expires. Upon exiting the hot press(either via the moving conveyor belt or a user that manually removes thecomposite mat), the composite mat may be moved into the cold press ofthe manufacturing apparatus to be cooled.

At an operation 406, the composite mat may be conveyed into the coldpress of the manufacturing apparatus and the cold press may press a pairof cold-platens to cool and shape the composite mat into a compositeboard. The cold press may be configured to exert a predetermined amountof pressure on the composite mat as the conveyor belt of themanufacturing apparatus moves the composite mat through the cold press.In some embodiments, the manufacturing apparatus may not include aconveyor belt, and may instead include an opening into which a user mayinsert the composite mat. The cold press may compress, cool, and/orshape the composite mat for a predetermined amount of time (e.g., basedeither on the length of the cold-platens and speed of the conveyor beltcarrying the composite mat, or a time determined based on thecharacteristics of the composite mat). In some embodiments, subsequentto cold pressing, the composite mat can be cut into boards which may beuseful for a roof cover board application.

Referring now to FIG. 5 , a block diagram of a composite boardmanufacturing system 500 is shown, in accordance with some embodimentsof the present disclosure. Composite board manufacturing system 500 mayinclude a manufacturing apparatus 502 and a controller 504. Controller504 may be a component of manufacturing apparatus 502 (e.g., a processorand/or display coupled to manufacturing apparatus 502) or may beexternal to manufacturing apparatus 502. Manufacturing apparatus 502 mayinclude a mat formation assembly stage 506, a conveyor belt assembly508, a hot press 510, a cold press 512, and sensors 514. Manufacturingapparatus 502 and its respective components 506-514 may be similar tomanufacturing apparatus 202, shown and described with reference to FIG.2 . Controller 504 may be configured to operate manufacturing apparatus502 to manufacture composite mats. In some instances, controller 504 mayreceive sensor data from sensors 514 that indicate one or morecharacteristics of a composite mat and adjust the operation ofmanufacturing apparatus 502 based on the sensor data (e.g., adjust aspeed of a conveyor belt of conveyor belt assembly 508, a temperature ofhot press 510, a temperature of cold press 512, etc.).

Controller 504 may include a processing circuit 516 and a communicationinterface 522. Processing circuit 516 may include a memory 518 and aprocessor 520, in some embodiments. Processing circuit 516 may beimplemented as a general-purpose processor, an application specificintegrated circuit (“ASIC”), one or more field programmable gate arrays(“FPGAs”), a digital-signal-processor (“DSP”), circuits containing oneor more processing components, circuitry for supporting amicroprocessor, a group of processing components, or other suitableelectronic processing components. Processor 520 may include an ASIC, oneor more FPGAs, a DSP, circuits containing one or more processingcomponents, circuitry for supporting a microprocessor, a group ofprocessing components, or other suitable electronic processingcomponents. In some embodiments, processor 520 may execute computer codestored in memory 518 to facilitate the activities described herein.Memory 518 may be any volatile or non-volatile computer-readable storagemedium capable of storing data or computer code relating to theactivities. According to an exemplary embodiment, memory 518 may includecomputer code modules (e.g., executable code, object code, source code,script code, machine code, etc.) for execution by processor 520.

Communication interface 522 may communicate with a communicationinterface 524 of manufacturing apparatus 502 via any synchronous orasynchronous network. Communication interface 522 may include one ormore communication interfaces that can communicate with the componentsof manufacturing apparatus 502. For example, controller 504 may receivedata from sensors 514 and/or control conveyor belt assembly 508, hotpress 510, and/or cold press 512 via communication interface 522. Basedon such sensor data and via communication interface 522, controller 504may transmit signals to the manufacturing apparatus 502 or devices(e.g., actuators or controllers) that operate the individual components506-514 to cause manufacturing apparatus 502 to form composite mats andmove the composite mats on conveyor belt assembly 508 (e.g., by moving aconveyor belt of conveyor belt assembly 508) through hot press 510and/or cold press 512 and/or change a position of the platens (e.g.,open or move closer together) of hot press 510 and/or cold press 512.

Upon a composite mat being assembled at mat formation assembly stage 506and/or placed on any component of manufacturing apparatus, processor 520may detect the composite mat and characteristics of the mat. Thecomposite mat may contain plastic and cellulose components such as paperand plastic fragments, as described herein, and/or liquid content (e.g.,water, milk, alcohol, soft drinks, etc.). In cases in which the liquidis water, water may be any aqueous solution in which water is thesolvent and that is diluted with any materials such as salt, sugar, orany other materials. In some cases, the water may be a component or aningredient of a liquid in the composite mat. Processor 520 may detectthe composite mat based on a user input and/or based on sensor data thatindicates the composite mat has been placed on manufacturing apparatus502 (e.g., on composite mat formation assembly stage 506, a conveyorbelt assembly, or between a pair of opposing hot-platens). In someembodiments, the user input and/or the sensor data may further indicatea current thickness or a desired thickness, a mat composition (e.g.,percentage of liquid, plastic, paper, or other materials), and/or amoisture content of the composite mat. Processor 520 may receive thesensor data and operate the manufacturing apparatus to create acomposite board that can act as roofing or side paneling as describedbelow.

Processor 520 may determine whether the composite mat has a liquidcontent that exceeds a threshold. Using the sensor data and/or a userinput, processor 520 may determine an amount of liquid (e.g., moisture)that is in the composite mat and/or a percentage of the composite matthat is made up of liquid. Processor 520 may retrieve a stored threshold(e.g., 3%) or a water or liquid content threshold, from memory 518 andcompare the determined amount of liquid or percentage to the thresholdto determine if the amount of liquid exceeds the threshold. In somecases, processor 520 may determine if the amount of liquid is within apredetermined range (e.g., 3%-25%).

In some embodiments, responsive to determining the amount of liquid doesnot exceed the threshold or is not within the predetermined range, thedata processing system may transmit a signal that causes a liquidreservoir 526 to release liquid onto the composite mat. Liquid reservoir526 may be a water reservoir and may contain liquid such as water, asdefined above, or any other liquid. Processor 520 may transmit a signalto a device (e.g., an actuator) that controls a position and/ororientation of liquid reservoir 526 to cause liquid reservoir 526 topump, discharge, spray or otherwise release liquid onto the compositemat to cause the composite mat to contain enough liquid to be above thethreshold or be within the range. In some embodiments, processor 520 maydetermine a difference or a distance between the amount of liquid in themat and the threshold or the range (e.g., by comparing the amount ofliquid to the threshold). In such embodiments, processor 520 may controlthe positioning of liquid reservoir 526 to release enough liquid ontothe composite mat to reach the threshold or range and then stop liquidreservoir 526 from releasing the liquid. Thus, liquid reservoir 526 doesnot need to be refilled at each instance that liquid reservoir 526releases liquid onto a composite mat and can instead be used to addliquid to composite mats during multiple instances. By implementing suchmethods, processor 520 can ensure composite mats contain enough liquidto be cooled during a state change from a superheated state to a gaseousstate.

Processor 520 may cause a pair of opposing hot-platens of themanufacturing apparatus to compress and heat a composite mat for apredetermined time period to a target thickness. The target thicknessmay be a target thickness for a first stage of compressing and heatingthe composite mat. For example, processor 520 may cause the pair ofopposing hot-platens to heat and melt the components of the compositemat to minimize the mat's thickness. Processor 520 may do so using a“position-controlled” method in which processor 520 retrieves a patternof position data from memory 518 and controls the positions of the pairof hot-platens using the pattern of position data for a predeterminedtime period. The pattern of position data may include the predeterminedtime period and predetermined distances between the platens at timeswithin the time period. Processor 520 may control the platens to be atthe corresponding positions throughout the time period specified in thepattern of position data. In one example, the pattern of position datamay only include one position. Sensors 514 may include sensors thatdetect the position of the hot-platens. The sensors may send data toprocessor 520 indicating the current position and processor 520 maytransmit signals to cause the hot-platens to maintain the positionidentified in the pattern of position data. Processor 520 may similarlycontrol the positions of the hot-platens for any positions of a positionpattern. Through the position-controlled method, processor 520 may heatand compress the composite mat into the target shape and/or thicknesswithout taking any pressure data into account.

In some embodiments, processor 520 may retrieve position data based on acurrent thickness of the mat and/or a target thickness for the mat. Forexample, processor 520 may receive sensor data and/or a user input thatindicates a current thickness and/or a target thickness for thecomposite mat. Processor 520 may use one or both of the thicknesses in alook-up table stored in memory 518 to identify the position data to useto control the positions of the hot-platens to form the composite matinto the target thickness. By using predetermined patterns to form acomposite mat shape, the data processing may ensure the hot-platens cancreate the composite mats without applying too much pressure anddeforming the composite mats (or breaking the manufacturing apparatus)or too little pressure and allowing too much superheated liquid withinthe mat to escape as gas (e.g., steam).

Processor 520 may receive indications of pressure the pair of opposinghot-platens exerts while compressing the composite mat from a pressuresensor (e.g., a pressure transducer). Processor 520 may receive suchpressure data during another time period in which processor 520 controlsthe positions of the hot-platens based on the pressure that thehot-platens are exerting on the composite mat. Processor 520 may receivethe pressure indications from the pressure sensors as the hot-platensheat and compress the composite mat and use the pressure indications tocontrol the positions of the hot-platens. For example, at the end of thetime period in which processor 520 controls the hot-platens using theposition-controlled method, processor 520 may use a“pressure-controlled” method to control the positions of thehot-platens. To do so, processor 520 may retrieve a target pressure(e.g., 50 psi), a pressure threshold, or a pressure range from memory518. Processor 520 may determine whether the pressure indications exceedor are within a predetermined range of the target pressure, threshold,or range by comparing the pressure indications to the respective target.

Responsive to determining the pressure indications do not exceed or arenot within a predetermined range of the target pressure, processor 520may determine new hot-platen positions for the hot-platens. Processor520 may determine a magnitude and/or a direction that the pressure isfrom the target pressure and determine a new position for thehot-platens to increase or decrease the pressure to reach the targetpressure according to the magnitude and/or direction. Processor 520 mayadjust the positions of the hot-platens using the determined positionsby transmitting signals that cause the hot-platens to either furtherclose in on the composite mat to increase the applied pressure orrelease the hot-platens to apply less pressure. Because the targetpressure may be a pressure that allows the liquid within the compositemat to superheat without changing states into a gas, by adjusting thepositions of the hot-platens to apply such pressure, processor 520 mayenable the composite mat to be heated at a constant pressure withoutturning the liquid contents of the mat into gas.

In some embodiments, processor 520 may use a position-controlled methodto maintain the constant pressure on the composite mat throughout thetime in which the composite mat is heated. For example, as describedabove, processor 520 may retrieve a position pattern from memory 518that processor 520 may use to transmit position data to the devicescontrolling the position of the hot-platens. The positions of theposition pattern may cause the platens to exert a constant orpredetermined pressure on the composite mat as the materials within themat melt. Because the amount of material within the mat that melts ispredictable, the positions may correspond to a constant or predeterminedpressure, thus enabling processor 520 to control the hot-platens toexert a constant or predetermined pressure on the hot-platens tosuperheat the liquid (e.g., water) until the mat is released from thepressure (e.g., from a position of the position pattern or from theconveyor belt moving the composite mat from the hot-platens).

Processor 520 may determine whether a pressing time period has expired.The pressing time period may be the time period in which the hot-platenspress the composite mat under both the position-controlled first stageand the pressure-controlled second stage, only the pressure-controlledsecond stage, or only a position-controlled stage in which processor 520heats the mat composite mat to the target temperature (e.g., in cases inwhich processor 520 maintains the constant pressure using positionpatterns instead of pressure data). The pressing time period may be apredetermined time period in which the hot-platens have been calculatedto be able to heat the composite mat to a target temperature. Thepressing time period may be controlled by a speed of the conveyor beltin embodiments in which the manufacturing apparatus includes conveyorbelt assembly 508 (e.g., processor 520 may control the speed of theconveyor belt so composite mats remain between the hot-platen models fora predetermined time period) or a time in which the hot-platens applypressure in embodiments in which the manufacturing apparatus is a staticpress without a conveyor belt. Processor 520 may compare an amount oftime that the composite mat has been compressed to the pressing timeperiod to determine whether the composite mat's core has been heated tothe target temperature. Responsive to determining the mat's core has notreached the target temperature (or that the time period has notexpired), processor 520 may repeatedly receive pressure data, comparethe pressure data to the target pressure, and adjust the positions ofthe hot-platens to maintain the pressure within a range of the targetpressure to ensure the hot-platens apply enough pressure on thecomposite mats so the liquid content can be superheated while the othercomponents melt. The range may have upper and lower bounds, just anupper bound, or just a lower bound. For example, in some embodiments,the range may be or include pressures above 25 psi. Processor 520 may doso until the core or average temperature of the composite mat reachesthe target temperature.

Once processor 520 determine the time period has expired, processor 520may transmit a signal that causes the hot-platens to release thecomposite mat. The signal may be a signal that causes the conveyor beltto move the composite mat away from the hot-platens or a signal thatcauses the hot-platens to change positions away from the composite matto create a gap between the composite mat and the platens or tootherwise minimize the amount of pressure the platens are applying.

Advantageously, by using a predetermined time period instead oftemperature data to determine when to release the composite mat,processor 520 may accurately determine when the composite mat has beenproperly heated. It can be difficult to determine the temperature ofcomposite mats using sensors because the outer surface of the mat mayquickly be heated to the temperature of the hot-platens while the heatis transferred throughout the mat. Thus, sensors that take thetemperature of the outer surface may not accurately indicate when themat has been heated. Because it can be difficult to insert sensors intothe composite mat to obtain a reading of the core temperature, processor520 may use the predetermined time period to more accurately determinewhen to stop heating the mat.

Upon releasing the composite mat from the pair of opposing hot-platens,the liquid in the composite mat may change state from its liquid stateto a gaseous state. The liquid may do so because the decrease inpressure may allow for the liquid to convert into a gas. For instance,for a liquid to boil (e.g., to change state from a liquid to a vapor)the vapor pressure of the liquid may exceed the ambient pressure of theliquid's environment. Because processor 520 controls the hot-platens tosubstantially increase the ambient pressure in the mat during pressing,the liquid may superheat and not turn into gas upon reaching its boilingpoint at normal pressure levels (e.g., one atmosphere). By releasing thecomposite mat, processor 520 may cause the pressure placed on thecomposite mat to be closer to the normal pressure levels, reducing theboiling point of the liquid within the mat without decreasing itstemperature, causing the liquid to almost instantaneously convert into agas upon relieving the pressure.

Advantageously, the conversion of the liquid within the mat to a gas maycause the mat to lose a large amount energy, and thus reduce itstemperature. For instance, an emission of steam from the mat can beclearly observed at the end of the hot-pressing event when panels aremade in accordance with this disclosure. This phase change requiresabout 2,258 Joules of energy per gram of water. For example, in somecases, an initial temperature decrease at the center of the mat can beas high as about 40-60° F. At a temperature of 300° F., a mat comprisedpredominantly of a mixture of paper and polyethylene has a specific heatcapacity of about 1 J/g/F. Thus, removing 1 J/g of energy results in atemperature decrease of about 1° F. If 2% of the mat, by mass, issuperheated water at the end of the hot-pressing cycle, and all of thissuperheated water is immediately converted to steam, which is emittedfrom the panel, then the expected temperature decrease would be about45.2° F. This relationship is illustrated with the equation below:

${\Delta T} = \frac{(L)\left( {2258\frac{J}{g}} \right)}{1.\frac{J}{gF}}$

where L is the liquid percentage of the mat when the mat is releasedfrom the hot-platens. Thus, the degree of the instantaneous temperaturedecrease will be proportional to the amount of superheated water thatcan be retained in the mat at the end of the pressing cycle.

Processor 520 may cause a pair of opposing cold-platens of themanufacturing apparatus to compress and cool the composite mat to asecond target temperature. The second target temperature may be atemperature (e.g., 138° F.) in which the mat's contents freeze orcongeal after melting under the hot-platens pressure and temperature.Processor 520 may transmit a signal to a device (e.g., an actuator or acontroller) that operates cold-platens to compress and cool thecomposite mat to the second target temperature before the cold-platensrelease the composite mat. In some embodiments, processor 520 maytransmit a signal to the conveyor belt to cause the conveyor belt tomove the composite mat through the cold-platens. In such embodiments,processor 520 may control the speed of the conveyor belt so thecold-platens may remain at a cool temperature and at a constant positionwhile the composite mat moves through the platens. Processor 520 maycontrol the speed so, by the time the composite mat exits thecold-platens, the composite has cooled to the second target temperature.

Advantageously, by using the systems and methods described herein and inembodiments in which processor 520 controls the speed of the conveyorbelt, the manufacturing apparatus may be created to be shorter (e.g.,have shorter cold-platens) and/or processor 520 may cause the conveyorbelt to move faster through the cold-platens while still enablingcomposite mats to be adequately cooled. The sudden cooling technique mayminimize any gradient heating that typically occurs after composite matsleave the hot-platens and/or cause a sudden drop in composite mattemperature that may significantly reduce the amount of time that thecomposite mats need to be cooled. Thus, the systems and methods enablemore composite mats to be manufactured more quickly and while requiringless space to do so.

In some embodiments, the hot-platens and/or cold-platens may be curvedto relieve the pressure that causes the liquid within the composite matto superheat. For example, the hot-platens may be curved upward at anend of the hot-platens that is proximate to the cold-platens. In suchembodiments, the conveyor belt may move a composite mat so thehot-platens may exert a constant pressure as the composite mat movesbetween the hot-platens to execute the sudden cooling effect describedherein. The conveyor belt may move the composite mat at a speed thatenables the center of the composite mat to heat to a target temperaturebefore the hot-platens curve upwards. Subsequent to reaching the targettemperature, the conveyor belt may continue moving the composite mat.Upon reaching the point that the hot-platens curve upwards, the pressurebeing applied to the mat may be relieved or released. Thus, the curvemay mechanically enable the sudden cooling effect without requiring acontroller to send a signal to move the hot-platens up or down, enablingthe hot-platens to remain in one position while heating multiplecomposite mats in sequence.

Moreover, in some embodiments, the cold-platens may be similarly curvedat a proximate end to the hot-platens. In such embodiments, thecold-platens may be immediately next to the hot-platens so there is nota gap between the hot and cold-platens. Advantageously, in suchembodiments, the composite mat may be suddenly cooled with the decreasein pressure caused by the curve in the hot-platens and then immediatelycooled by the cold platens, enabling for composite mats to be cooledquicker, for shorter manufacturing apparatuses to be created, and forcomposite boards to be manufactured without sending signals to move thehot and/or cold-platens.

Referring now to FIG. 6A, a block diagram illustrating a sequence ofheating and compressing a composite mat using a hot press in two stagesis shown, in accordance with some embodiments of the present disclosure.In a first stage 602, a hot press controller 604 may control a positionof hot-platens 606 and 608 of a hot press to heat and compress acomposite mat 610 to a particular shape and/or thickness. Hot presscontroller 604 may be similar to controller 504, shown and describedwith reference to FIG. 5 . Composite mat 610 may be a composite mat asdescribed herein and include liquid content 612. Such liquid content maybe or include liquid that was added to composite mat 610 to ensurecomposite mat 610 contained enough liquid for hot press controller 604to implement the sudden cooling effect described herein and other liquidthat is commonly found in landfill waste (e.g., from water bottles,paper fragments, soda bottles, milk cartons, or any other type ofwaste).

Hot press controller 604 may identify a thickness of composite mat 610and retrieve a pressing pattern that corresponds to the thickness frommemory. The pressing pattern may include different positions ofhot-platens 606 and/or 608 over time while hot-platens 606 and 608 arecompressing and heating composite mat 610. In one example, the pressingpattern may include a constant position that hot press controller 604may maintain throughout a time period. Hot press controller 604 maytransmit position data 614 that corresponds to the pressing pattern to adevice controlling the positions of hot-platens 606 and 608. Hot presscontroller 604 may control the position data of hot-platens 606 and 608so composite mat 610 is at a predetermined thickness at the end of atime period of the pressing pattern. In some embodiments, thepredetermined thickness may be higher than a target thickness for theentire hot pressing event because the pressure hot-platens 606 and 608exert during the next stage may cause composite mat 610 to becomethinner (e.g., hot press controller 604 may control hot-platens 606 and608 so composite mat 610 will have a thickness of 0.510″ after firststage 602 and a thickness of 0.500″ after a second heating stage).

Hot press controller 604 may control hot-platens 606 and 608 withoutreceiving any data from pressure sensors 616 and/or 618. That beingsaid, the positions of the pressing patterns may cause hot-platens 606and 608 to exert a pressure that allows for hot-platens 606 and 608 toheat composite mat 610 so liquid content 612 can exceed a boiling pointwithout converting to gas. The pressing pattern may do so because thepatterns are associated with individual composite mat targetthicknesses. For example, composite mats may lose thickness at apredictable rate as they are being compressed at a predeterminedtemperature. Thus, different target thicknesses may be associated withdifferent positions. Hot press controller 604 may identify the positionsof the pattern associated with a target 5/16″ thickness at differenttimestamps during a hot press event in which the hot-platens arecompressing a composite mat to have a 5/16″ thickness and transmitposition data 614 to change the position of hot-platens 606 and 608 atthe positions of the corresponding timestamps. During this pressingprocess, sensors may continuously transmit position data to hot presscontroller 604 indicating the positions of hot-platens 606 and 608. Hotpress controller 604 may receive the position data and control thepositions of hot-platens 606 and 608 to be at the set positions based onthe position data. Because the thickness of composite mat 610 ispredictable, the positions may cause hot-platens 606 and 608 to apply apressure that enables hot-platens 606 and 608 to superheat liquidcontent 612.

In a second stage 620, hot press controller 604 may control hot-platens606 and 608 to compress and heat composite mat 610 using apressure-controlled method. For example, after a time period in whichhot press controller 604 operates the hot-platens 606 in first stage 602is over, hot press controller 604 may control the hot-platens 606 and608 based on pressure data 622 that hot press controller 604 receivesfrom pressure sensors 616 and 618. Hot press controller 604 may beconfigured to cause hot-platens 606 and 608 to maintain a predeterminedpressure on composite mat 610. Hot press controller 604 may receivepressure data 622 and compare the data to the predetermined pressure.Responsive to determining pressure data 622 is outside of apredetermined range of the predetermined pressure, hot press controller604 may transmit position data 624 to the device controlling thepositions of hot-platens 606 and 608 to move the position of hot-platens606 and 608 to exert a pressure at the predetermined pressure or withinthe range. In some embodiments, the predetermined pressure and/or rangemay allow hot-platens 606 and 608 to heat composite mat 610 to a targettemperature without boiling liquid content 612.

In some embodiments, hot press controller 604 may use apressure-controlled control method to press and heat composite mat 610during first stage 602. In such embodiments, hot press controller 604may press composite mat 610 using a fixed pressure to cause compositemat 610 to have a fixed thickness. In some embodiments, hot presscontroller 604 may cause hot-platens to exert a constant pressure (e.g.,a predetermined pressure or a pressure within a predetermined range) oncomposite mat 610 across both first stage 602 and second stage 620.

Referring now to FIG. 6B, a block diagram illustrating a continuation ofthe sequence of FIG. 6A in which the composite mat is cooled using asudden cooling technique is shown, in accordance with some embodimentsof the present disclosure. The sequence may include a third stage 626 inwhich hot press controller 604 sends a release command 628 to causehot-platens 606 and 608 to release composite mat 610 from the pressuresensors 616 and 618 were exerting on composite mat 610. The command maybe a signal to the devices controlling the position of hot-platens 606and 608 and/or a command to a conveyor belt assembly (not shown) thatcauses a conveyor belt moving composite mat to move composite matthrough hot-platens 606 and 608. In some embodiments, because liquidcontent 612, shown and described with reference to FIG. 6A has beensuperheated upon composite mat 610 being released from hot-platens 606and 608, liquid content may instantaneously convert into a gas 630 uponhot-platens 606 and 608 releasing composite mat 610, thus releasing theliquid content from composite mat 610 and quickly reducing thetemperature of composite mat 610.

It should be understood that first stage 602, second stage 620, andthird stage 626 may be or include one hot-pressing stage in whichcomposite mat 610 is heated between hot-platens 606 and 608. After thehot pressing-stage, composite mat 610 may be cooled to a targettemperature in a cold-pressing stage by cold-platens as describedherein.

In some embodiments, the composite mat may have a thickness of greaterthan about 0.2 inches and less than about 1.5 inches and/or a densitygreater than about 45 pcf and less than about 70 pcf after thecold-pressing stage.

FIG. 7 is a flow diagram of an example process 700 for forming acomposite mat into a composite board using a sudden cooling technique,in accordance with some embodiments of the present disclosure. Process700 can be performed using a manufacturing apparatus (e.g.,manufacturing apparatus 502) and/or a data processing system (e.g.,controller 504). Process 700 may include more or fewer operations andthe operations may be performed in any order. Performance of process 700may enable the manufacturing apparatus to manufacture, from wastematerials, a composite board that can be used for roofing and/or siding.By performing the systems and methods, the data processing system mayenable composite mat manufacturing apparatuses to cool composite matsmore quickly than under previous methods. Thus, manufacturingapparatuses may manufacture composite boards faster and/or may becreated to take up less space with shorter cooling platens.

At an operation 702, the data processing system may detect a compositemat. The composite mat may contain plastic and cellulose components suchas paper and plastic fragments, as described herein, and/or liquidcontent (e.g., water, milk, alcohol, soft drinks, etc.). The dataprocessing system may detect the composite mat based on a user inputand/or based on sensor data that indicates the composite mat has beenplaced on the manufacturing apparatus (e.g., on a composite matformation assembly stage, a conveyor belt assembly, or between a pair ofopposing hot-platens). In some embodiments, the user input and/or thesensor data may further indicate a thickness, a mat composition, and/ora moisture content of the composite mat. The data processing system mayreceive the sensor data and/or user input and operate the manufacturingapparatus to create a composite board that can act as roofing or sidepaneling as described below.

At an operation 704, the data processing system may determine whetherthe composite mat has a liquid content that exceeds a threshold. Usingthe sensor data and/or a user input, the data processing system maydetermine an amount of liquid (e.g., moisture) that is in the compositemat and/or a percentage of the composite mat that is made up of liquid.The data processing system may retrieve a stored threshold from memoryand compare the determined amount of liquid or percentage to thethreshold to determine if the amount of liquid exceeds the threshold. Insome cases, the data processing system may determine if the amount ofliquid is within a predetermined range.

At an operation 706, responsive to determining the amount of liquid doesnot exceed the threshold or is not within the predetermined range, thedata processing may transmit a signal that causes a liquid reservoir torelease liquid onto the composite mat. The liquid reservoir may containliquid such as water or any other liquid. The data processing system maytransmit a signal to a device (e.g., an actuator or controller) thatcontrols a position of the liquid reservoir to cause the liquidreservoir to pump, dispense, spray, or otherwise release liquid onto thecomposite mat to cause the composite mat to contain enough liquid to beabove the threshold or be within the range. In some embodiments, thedata processing system may determine a difference or a distance betweenthe amount of liquid in the mat and the threshold or the range (e.g., bycomparing the amount of liquid to the threshold). In such embodiments,the data processing system may control the positioning of the liquidreservoir to release enough liquid onto the composite mat to reach thethreshold or range and then stop the composite mat from releasing theliquid. Thus, the liquid reservoir may not need to be refilled at eachinstance that the reservoir releases liquid onto a composite mat and caninstead be used to add liquid to composite mats during multipleinstances. By implementing such methods, the data processing system canensure composite mats contain enough liquid to be cooled during a statetransfer from a superheated state to a gaseous state.

At an operation 708, the data processing system may cause a pair ofopposing hot-platens of the manufacturing apparatus to compress and heata composite mat for a predetermined time period to a target thickness.The target thickness may be a target thickness for a first stage ofcompressing and heating the composite mat. For example, the dataprocessing system may cause the pair of opposing hot-platens to heat andmelt the components of the composite mat to minimize the mat'sthickness. The data processing system may do so using a“position-controlled” method in which the data processing systemretrieves a pattern of position data from memory and controls thepositions of the pair of hot-platens using the pattern of position datafor a predetermined time period. The pattern of position data mayinclude the predetermined time period and positions of the hot-platenswithin the time period. In some embodiments, the data processing systemmay retrieve position data based on a current thickness and/or a targetthickness of the mat. For example, the data processing system mayreceive sensor data and/or a user input that indicates the currentthickness and/or a target thickness of the composite mat. The dataprocessing system may use one or more of the thicknesses in a look-uptable stored in memory to identify the position data to use to controlthe positions of the hot-platens to form the composite mat into thetarget thickness. By using predetermined patterns to form a compositemat shape, the data processing may ensure the hot-platens may create thecomposite mats without applying too much pressure and deforming thecomposite mats (or breaking the manufacturing apparatus) or too littlepressure and allowing any superheated liquid within the mat to escape asgas.

At an operation 710, the data processing system may receive, from apressure sensor (e.g., a pressure transducer), indications of pressurethe pair of opposing hot-platens exerts while compressing the compositemat. The data processing system may receive such pressure data duringanother time period in which the data processing system is controllingthe positions of the hot-platen based on the pressure that thehot-platens are exerting on the composite mat. The data processingsystem may receive the pressure indications from the pressure sensors asthe hot-platens are heating and compressing the composite mat and usethe pressure indications to control the positions of the hot-platens.For example, at the end of the time period in which the data processingsystem controls the hot-platens using the position-controlled method,the data processing system may use a pressure-controlled method tocontrol the positions of the hot-platens. To do so, at an operation 712,the data processing system may retrieve a target pressure from memory.The data processing system may determine whether the pressureindications exceed or are within a predetermined range of the targetpressure by comparing the pressure indications to the target.

Responsive to determining the pressure indications do not exceed or arenot within a predetermined range of the target pressure, at an operation714, the data processing system may determine new hot-platen positionsfor the hot-platens. The data processing system may determine amagnitude and/or a direction that the pressure is from the targetpressure and determine a new position for the hot-platens to increase ordecrease the amount of pressure to reach the target pressure accordingto the magnitude and/or direction. At an operation 716, the dataprocessing system may adjust the positions of the hot-platens using thedetermined positions by transmitting signals that cause the hot-platensto either further close in on the composite mat to increase the appliedpressure or release the hot-platens to apply less pressure. Because thetarget pressure may be a pressure that allows the liquid within thecomposite mat to superheat without changing state into a gas, byadjusting the positions of the hot-platens to apply such pressure, thedata processing system may enable the composite mat to be heated at aconstant pressure without turning the liquid contents of the mat intogas.

At an operation 718, the data processing system may determine whether apressing time period has expired. The pressing time period may be thetime period in which the hot-platens press the composite mat under boththe position-controlled first stage and the pressure-controlled secondstage or only the pressure-controlled second stage. The pressing timeperiod may be a predetermined time period that enables the hot-platensto heat the composite mat to a target temperature. The pressing timeperiod may be controlled by a speed of the conveyor belt in embodimentsin which the manufacturing apparatus includes the conveyor belt assembly(e.g., the data processing system may control the speed of the conveyorbelt so the composite mats remain between the hot-platen models for apredetermined time period) or a time in which the hot-platens applypressure in embodiments in which the manufacturing apparatus is a staticpress without a conveyor belt. The data processing system may compare anamount of time that the composite mat has been compressed to thepressing time period to determine whether the composite mat's core hasbeen heated to the target temperature. Responsive to determining thatthe time period has not yet expired, the data processing system mayrepeatedly perform operations 710-718 to ensure the hot-platens applyenough pressure on the composite mats so the liquid content can besuperheated without turning into a gas while the other components meltuntil the core or the average temperature of the composite mat reachesthe target temperature.

However, responsive to determining that the time period has expired, atan operation 720, the data processing system may transmit a signal thatcauses the hot-platens to release the composite mat. The signal may be asignal that causes the conveyor belt to move the composite mat away fromthe hot-platens or a signal that causes the hot-platens to changepositions away from the composite mat to create a gap between thecomposite mat and the platens or to otherwise minimize the amount ofpressure the platens are applying.

Advantageously, by using a predetermined time period instead oftemperature data to determine when to release the composite mat, thedata processing system may accurately determine when the composite mathas been properly heated. It can be difficult to determine thetemperature of composite mats using sensors because the outer surface ofthe mat may quickly be heated to the temperature of the hot-platenswhile the heat is transferred throughout the mat. Thus, sensors thattake the temperature of the outer surface may not accurately indicatewhen the core layer of the mat has been sufficiently heated. Because itcan be difficult to insert sensors into the composite mat to obtain areading of the core temperature, the data processing system may use thepredetermined time period to more accurately determine when to stopheating the mat.

Upon releasing the composite mat from the pair of opposing hot-platens,the liquid in the composite mat may change state from its liquid stateto a gaseous state. The decrease in pressure on the mat may allow forthe stored liquid to convert into a gas and be released from the mat.For instance, for a liquid to boil (e.g., to change state from a liquidto a vapor) the vapor pressure of the liquid must exceed the ambientpressure. Because the data processing system controls the hot-platens tosubstantially increase the ambient pressure in the mat during pressing,the liquid may superheat and not turn into gas upon reaching its boilingpoint at normal pressure levels (e.g., one atmosphere). By releasing thecomposite mat, the data processing system may cause the pressure placedon the composite mat to be closer to the normal pressure levels,reducing the boiling point of the liquid within the mat withoutdecreasing its temperature, causing the liquid to almost instantaneouslyconvert into a gas upon relieving the pressure and for the coretemperature to decrease.

At an operation 722, the data processing system may cause a pair ofopposing cold-platens of the manufacturing apparatus to compress andcool the composite mat to a second target temperature. The second targettemperature may be a temperature (e.g., 138° F.) in which the mat'scontents freeze or congeal after melting under the hot-platens pressureand temperature. The data processing system may transmit a signal to adevice (e.g., an actuator or a controller) that operates thecold-platens to compress and cool the composite mat to the second targettemperature before the cold-platens release the composite mat. In someembodiments, the data processing system may transmit a signal to theconveyor belt to cause the conveyor belt to move the composite matthrough the cold-platens. In such embodiments, the data processingsystem may control the speed of the conveyor belt so the cold-platensmay remain at a cool temperature and at a constant position while thecomposite mat moves through the platens. The data processing system maycontrol the speed so, by the time the composite mat exits thecold-platens, the composite mat has cooled to the second targettemperature.

Systems that implement the process described herein may differ fromsystems that do not use such processes methods described herein becausesuch systems often require the pressure to be released (e.g.,periodically released or at pseud-random intervals) to move the matusing a conveyor belt. Consequently, in such implementations, the liquidoften turns to steam and is released during hot-pressing, which may stopthe sudden cooling effect from occurring at the end of the hot pressingevent as described herein.

In some embodiments of the present disclosure, a method for producing acomposite board comprised of polyethylene and cellulose is described.The method may include forming a mat comprised of polyethylene andcellulose components wherein the mat has a moisture content of about 3%or greater; subjecting the mat to opposing hot-platens having ahot-platen temperature of about 350-450° F.; and simultaneouslycompressing the mat at a pressure not less than about 25 psi for a firsttime period sufficient for a center of the mat to reach a temperature ofabout 260-340° F.; relieving applied pressure on the mat; subjecting themat to opposing cold-platens having a cold-platen temperature of lessthan about 120° F. and simultaneously compressing the mat at a pressureof about 5-40 psi for a second time period sufficient for the center ofthe mat to reach a temperature that is less than about 220° F.

In some embodiments, the polyethylene and cellulose components arefragments. In some embodiments, the polyethylene component is present ata level of about 20-50%. In some embodiments, the panel has a density ofabout 45-65 pounds per cubic foot. In some embodiments, the panel has athickness of about 0.150-1.000 inches.

In some embodiments, the temperature of the mat decreases by greaterthan 10° F. in a period of less than 5 seconds when pressure is relievedon the mat. In some embodiments, the temperature of the mat decreases bygreater than 30° F. in a period of less than 5 seconds when pressure isrelieved on the mat. In some embodiments, the temperature of the matdecreases by greater than 50° F. in a period of less than 5 seconds whenpressure is relieved on the mat. In some embodiments, the mat iscomprised of polyethylene, cellulose, and other components, includingsheet goods and/or particles.

In some embodiments, a mat is formed based on a mixture of cellulose andplastic fragments and a water content of about 3% or greater. The matmay be heated and compressed in a press for a period of about 2-15minutes such that the core of the mat reaches a temperature of about260-340° F. and the pressure exerted on the mat during the hot-pressingevent is never less than about 25 psi in order to retain 0.5% or greaterwater content in the mat in a superheated state. Immediately afterhot-pressing, pressure on the mat may be relieved such that thesuperheated water within the mat is abruptly converted to steam, whichresults in a sudden cooling effect.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected,” or“operably coupled,” to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable,” to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations may be expressly set forth herein for sakeof clarity.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.” Further, unlessotherwise noted, the use of the words “approximate,” “about,” “around,”“substantially,” etc., mean plus or minus ten percent.

The foregoing description of illustrative embodiments has been presentedfor purposes of illustration and of description. It is not intended tobe exhaustive or limiting with respect to the precise form disclosed,and modifications and variations are possible in light of the aboveteachings or may be acquired from practice of the disclosed embodiments.It is intended that the scope of the invention be defined by the claimsappended hereto and their equivalents.

What is claimed is:
 1. A method for producing a composite boardcomprised of plastic and cellulose, the method comprising: transmitting,by a processor, a first signal to one or more pairs of opposinghot-platens of a manufacturing apparatus, the one or more pairs ofopposing hot-platens heating and compressing a composite mat comprisingplastic, cellulose, and water, the composite mat having a core at amidpoint between a first end and a distal end of the composite mat,receipt of the first signal causing the one or more pairs of opposinghot-platens to compress and heat the composite mat; receiving, by theprocessor from a pressure sensor coupled to the one or more pairs ofopposing hot-platens, indications of pressure the one or more pairs ofopposing hot-platens exerts while compressing the composite mat; basedon the indications, transmitting, by the processor, a second signal tothe one or more pairs of opposing hot-platens, receipt of the secondsignal causing the one or more pairs of opposing hot-platens to heat andcompress the composite mat at substantially a first pressure tosuperheat the water such that a temperature of the water remains above aboiling temperature of the water at a standard atmospheric pressurewithout the water changing from a liquid state to a gaseous state for afirst time period sufficient for the core of the composite mat to reacha first target temperature; transmitting, by the processor, a thirdsignal to the one or more pairs of opposing hot-platens, receipt of thethird signal causing the one or more pairs of opposing hot-platens torelease the composite mat from the first pressure after the first timeperiod, wherein releasing the pressure on the composite mat causes thewater in the composite mat to change from a liquid state to a gaseousstate; and transmitting, by the processor, a fourth signal to a one ormore pairs of opposing cold-platens of the manufacturing apparatus,receipt of the fourth signal causing the one or more pairs of opposingcold-platens to compress and cool the composite mat for a second timeperiod sufficient for the core of the composite mat to reach a secondtarget temperature.
 2. The method of claim 1, wherein receipt of thefirst signal further causes the one or more pairs of opposinghot-platens to compress the composite mat at pressures above the firstpressure for a third time period before the first time period.
 3. Themethod of claim 2, wherein the first pressure is about 50 psi or less,and the pressures at which the one or more pairs of opposing hot-platenscompress the composite mat in the third time period are between about600 psi and about 800 psi.
 4. The method of claim 1, wherein receipt ofthe first signal further causes the one or more pairs of opposinghot-platens to compress the composite mat to a predetermined thicknesswithin a third time period before the first time period.
 5. The methodof claim 4, further comprising retrieving, during the third time periodby the processor based on a thickness of the composite mat, hot-platenposition data from a memory; wherein transmitting the first signaladjusts a position of the one or more pairs of opposing hot-platensaccording to the hot-platen position data.
 6. The method of claim 5,wherein the hot-platen position data comprises a pattern of time periodsand predetermined distances between the one or more pairs of opposinghot-platens during the time periods, the pattern based on thepredetermined thickness of the composite mat.
 7. The method of claim 1,wherein transmitting the second signal to the one or more pairs ofopposing hot-platens comprises: receiving, from the pressure sensor,indications of a current pressure that the one or more pairs of opposinghot-platens are exerting on the composite mat; determining that theindications of the current pressure are below a pressure threshold fromthe first pressure; and responsive to receiving the indications,transmitting the second signal to adjust a position of the one or morepairs of opposing hot-platens to exert a pressure at substantially thefirst pressure.
 8. The method of claim 1, in which a temperature of thecore of the composite mat decreases by greater than 30 degreesFahrenheit in a period of less than 5 seconds when the one or more pairsof opposing hot-platens release the composite mat from the firstpressure.
 9. The method of claim 1, the method further comprising:causing, by the processor, a first amount of water to be dispensed froma water reservoir into the composite mat to increase a total amount ofwater that is in the composite mat or within the plastic or cellulose.10. The method of claim 9, further comprising: receiving, by theprocessor, water content data from a moisture sensor, the water contentdata comprising an amount of water that is within the composite mat orwithin the plastic and cellulose; comparing, by the processor, theamount of water to a water content threshold; and wherein causing thefirst amount of water to be dispensed from the water reservoir to thecomposite mat or the plastic and cellulose is performed responsive todetermining that the amount of water is below the water contentthreshold.
 11. The method of claim 10, wherein the water contentthreshold of the composite mat is about 3% or greater.
 12. The method ofclaim 1, wherein the first target temperature is between about 250degrees Fahrenheit and 350 degrees Fahrenheit and the second targettemperature is less than about 220 degrees Fahrenheit.
 13. The method ofclaim 12, wherein the second target temperature is less than about 200°F.
 14. The method of claim 12, wherein the second target temperature isless than about 190° F.
 15. The method of claim 1, wherein a temperatureof the one or more pairs of opposing hot-platens is in a range of about300 degrees Fahrenheit to about 420 degrees Fahrenheit.
 16. The methodof claim 1, wherein a temperature of the one or more pairs of opposingcold-platens is in a range of about 20 degrees Fahrenheit to about 120degrees Fahrenheit.
 17. The method of claim 16, wherein the one or morepairs of opposing cold-platens compress the composite mat in the secondtime period at a second pressure between about 5 psi and 40 psi.
 18. Themethod of claim 1, wherein plastic and cellulose in the composite matinclude individual fragments comprising discrete paper layers andplastic layers.
 19. The method of claim 1, wherein the plastic in thecomposite mat comprises polyethylene fragments and the cellulose in thecomposite mat comprises paper fragments.
 20. The method of claim 1,wherein the composite mat is comprised of top and bottom outer facerlayers with a melt-point greater than about 350° F. and a core layercomprised of a mixture of paper fragments and plastic fragments.